So I just got this boat. It has a painted plywood roof, but it's been neglected for many years, and the paint has begun to chip/peel. Parts of the roof are a bit rotten, and most of it is damp when I chip off the paint. Overall though, the roof seems good enough to be worth saving - it should be good so long as noone goes jumping around on it.

So, the question: I figure before painting over it it has to dry - I don't want to seal the moisture in for it to rot some more. In order to dry it, do I need to remove ALL the old paint? Some of it's still good, and it'd take a lot more work and paint if I did that. Or is it at all reasonably to think the wood will dry out through the chipped away parts (which are at most 2 feet away from painted over parts).